Photo- and heat-sensitive materials having on a support a photo- and heat-sensitive layer containing a diazo compound and a coupler have so far been known. Specifically, the recording materials of this type use the combination of a photo decomposable diazo compound, a coupler and a heat fusible substance, and take advantage of the coupling reaction between the diazo compound and the coupler, which takes place by heating to produce a color, and the decomposition of the diazo compound which takes place by exposure to light in the photolysis wave length region of the diazo compound, and thereby the above-described coloring reaction is hindered to effect the fixation. Therefore, the photo recording can be achieved by imagewise exposing the above-described recording material to light in the foregoing wave length region, and then heating the material up to a temperature higher than the melting point of the heat fusible substance. On the other hand, the heat-sensitive recording can be achieved by carrying out the heat recording, and then optically exposing all over the surface of the recording layer. Accordingly, when the above-described recording material is employed as a heat-sensitive recording material, the recorded image which has received fixation has a merit that it does not suffer from unnecessary color production in the background area, that is, it has excellent keeping quality, which is different from the case of heat-sensitive recording materials of leuco dye coloration type.
However, in analogy with the heat-sensitive recording material of leuco dye coloration type, the foregoing recording material causes fog during storage prior to processings, and so on. That is, it is insufficient mainly in freshness keeping property Therefore, various recording materials have so far been proposed with the intention of improving in freshness keeping property.
Among those recording materials, the recording material proposed by us (in Japanese Patent Application (OPI) No. 65043/83 (the term "OPI" as used herein means an unexamined published application)) is characterized by enmicrocapsulation of at least one component taking part in a color-producing reaction, e.g., at least either a diazo compound or a coupler, which involves forming a capsule wall around a core substance, which comprises at least one component participating in the color-producing reaction, through polymerization, whereby achieving an improvement in freshness keeping property without attend by lowering of a recording speed and a color density of developed image.
However, conventional recording materials, including the above-described recording material which utilizes enmicrocapsulation, are inferior in transparency. Therefore when images colored in various tints, e.g., red, blue, yellow, etc., are formed therein, the images become darkish, and lack in clearness. In addition, the whiteness in the background area is insufficient. More specifically, when color images recorded in a photo- and heat-sensitive layer provided on a transparent support are projected with an overhead projector (OHP) the conventional photo- and heat-sensitive recording materials suffer from the defects that the projected background looks darkish, so the contrast is lowered as a whole; and the projected color images look dull, too. Further, when multicolor recording is carried out using a photo- and heat-sensitive recording material in which two or more of photo- and heat-sensitive recording material in which two or more of photo- and heat-sensitive layers differing in color of the image to be produced are superposed upon one another, conventional recording materials have a problem that they are inferior in the reproducibility of mixed color in every overlapped area of images colored in different tints.
Though it is certain that these problems can be solved by the use of silver salt color photographic materials, these photographic materials also have different problems that they are expensive, and require a complex and time-consuming photographic processing in forming recorded images.